Catalytic conversion of hydrocarbons



United States Patent 3,194,754 CATALYTIC CONVERSEON 0F HYDRO'CARBONSFrank 1. Fahnestocic, Roslyn Harbor, N.Y., assignor to Socony Mobil OilCompany, Inc., a corporation or New York No Drawing. Originalapplication Dec. 20, 1961, er. No. 160,904. Divided and this applicationApr. 13, 1964, Ser. No. 359,484

7 Claims. (Cl. 208-120) This application is a division of my pendingapplication, Serial Number 160,904, filed December 20, 1961, nowabandoned.

This invention has to do with a method for the optimum utilization ofthe high efliciency of a recently developed group of catalytic materialsuseful for the conversion of gas oils to gasoline.

At the present time, catalysts for the cracking of gas oils to gasolineare various forms of amorphous complexes of silica and alumina,frequently with minor additions of various metals, etc., for variouspurposes. As such materials, there are used pellets and granular materials of the nature of clays, acid-washed clays, co-precipitatedcomplexes of silica and alumina, co-gelled complexes of silica andalumina, co gelled complexes of silica and alumina in the form of beads,microspheres, and the like. Typical of these is a specific bead-formcatalyst, hereinafter spoken of as conventional catalyst, which isproduced by co-gelation, washing, and base exchanging to free of alkalimetals, drying, and calcining, giving rise to an amorphoussilica-alumina complex, containing a small amount of chromia, and alsocombining a small amount of fine material of specified size and of thesame composition as the finished bead derived from a prior preparation.

A more recently developed group of catalytic materials exhibiting highlydesirable properties for the conversion of hydrocarbons are crystallinealumino-silicate complexes. These are materials of the general nature ofzeolites, having an ordered crystalline structure, generally having beentreated to substantially reduce or eliminate alkali metals, andfrequently base-exchanged, as with alkaline earth compounds, or as withrare-earth compounds to incorporate at least a portion of the alkalineearth element or rare-earth element or both in the crystallinestructure. One such material of this kind may be prepared by startingwith the commercial material known as Linde 13X molecular sieve, treatedby base exchange to incorporate rare-earth ions. Such catalysts,themselves, form no part of this invention.

These catalysts have capabilities quite diiferent from the conventionalamorphous silica-alumina complexes, as may be shown from the followingdata.

The data of Table I was derived from the comparison of the conventionalcatalyst previously spoken of and a catalyst prepared by incorporatingabout 7% of rare-earth exchanged 13X crystalline alumino-silicate andabout 34% by Weight of alumina fines in a co-gelled amorphous complex ofsilica-alumina. In the table, this is designated Catalyst A.

BJMJM Patented July 13, 1%65 Table IContinued COMPARATIVE CRACKING [2LHSV Mid-Continent gas oil at 930 F. ave. reactor temp] Oat/oil Ratio Vol./Vol 4 4 Conv., Percent Vol 59. 2 41. 0 O4-free Gasoline 45. 5 30. 5Percent Vol. Charge 2 Gasoline/Conv., Percent-.. 76. 8 76. O GasolineOctane No.2

Motor (leaded) +3 ml. of TEL 87. 1 85.9 Research (leaded) +3 ml. TEL 97.6 98.6

Light East Texas gas oil cracked over catalyst in static bed at 1.0LHSV, 10 minutes on stream and 875 F.

' 2 356 F. at percent gasoline.

types of operation and existing equipment without substantial change inthe physical characteristics of either.

This invention is based in part upon the fact that in an operationwherein a particle form catalyst moves cyclically through a reaction anda regeneration, such as the well known moving bed and fluidized bedoperations, a very finely divided solid material added to the catalyststream is largely deposited upon and held by the surface of the catalystparticles.

For example, in a moving bed operation utilizing bead catalyst, such asthe conventional catalyst above referred to, the beads being about inchin average diameter, if a solid material ground to particle sizes of theorder of l015 microns be added to the catalyst stream, it Will readilyadhere to and coat the surface of the particles, and will be retainedthereon under a Wide variety of conditions for extended periods of time.

By applying this principle to the use of the crystallinealumino-silicate catalytic materials, the entire amount of thecrystalline material so added is readily available for its contributionto the overall catalytic action, while the carrier, if it be a catalyst,is still available, as usual, for its function. Since the reactants donot have to penetrate or diffuse into the amorphous matrix to reach thecrystalline catalyst, its activity is not hampered by any diffusionlimitations which may arise from a matrix in which it might be embedded.Further, not being embedded in a matrix, it is not competing in reactionor for reactants with a surrounding material present in much greateramount. All of these considerations imply either a greater amount of adesired reaction with the same amount of crystalline catalyst, or sincethese crystalline catalysts usually operate at lower temperature levelsthan the amorphous silica-alumina catalysts and frequently givedifferent product distribution patterns for the same temperature, ascontrasted with the amorphous materials, a new degree of control overthe conversion operations may be attained.

This method of handling may be utilized with any particle-form material,Whether it be beads, pellets, granules, microspheres, or the like, andin any process wherein the particle-form material moves cyclicallythrough reaction and regeneration. It may be used upon any particle-form carrier Whether the carrier itself be a catalyst for thedesired operation, or some portion thereof,

Q of the finely divided crystalline catalyst before loading into thereactor.

Of course, in moving catalyst systems, such as the mov ing bed systems,a certain amount of abrasion of the particle-form material occurs, andit is customary to remove the tines so produced by an elutriationprocess. In fluidized bed processes, it is usually customary to removelines from effluent vapors and return them to the bed. In either case,it is obvious that the added crystalline materials will in part travelwith and be handled with the normally appearing fines. In elutriationremoval or". fines the so-removed crystalline catalytic material willnot be economically substantial in amount, as will be notedsubsequently.

In a moving bed, or TCC process, of airlift type, having a capacity of20,000 barrels per day of gas oil charge, the inventory of beadcatalyst, such as the conventional catalyst above noted, in theoperating portion of the unit is about 600 tons, circulated at a rate ofabout 475 tons per hour. (Dependent upon other factors, this circulationrate may vary within the range 350-550 tons per hour.) With theconventional catalyst above referred to a normal attrition rate of notabove 1.5 tons per day is experienced, which material is removed asfines through elutriation.

The addition of crystalline catalytic material, to the extent of about4% to 5% by weight of the total inventory, i.e., about 30 to 40 tons ofthe material, will result in conversions of hydrocarbons with resultsquite similar to those set forth in the comparison of operations setforth in Table I set forth above. Of this material, about 300 pounds perday will be lost through the elutriation operation. The remainder willremain on the bead catalyst surfaces through the cycles of reaction andregeneration.

The terms crystalline catalytic material and crystallinealumina-silicate catalytic material used herein embrace alumino-silicatematerials of ordered crystalline structure and generally zeoliticnature, with definite ratios of silica and alumina, and frequently withsignificantly less alkali metal content than that necessary to give thesalt form of the compound. The terms also embrace such materials inwhich at least a portion of the alkali metal is replaced by alkalineearth metal ions or by rareearth ions.

The size of the powdered crystalline alumino-silicate material which isadded depends upon the nature or size of the carrier to which it isadded. In moving bed systems, which normally use beads or particles ofabout 0.1 inch minimum average diameter, an upper limit of size of aboutmicrons is desirable beyond which the coating phenomenon does not occur.There is no lower size limit, since the finer the material, the betterthe adherence. With carrier particles of about 0.1 inch averagediameter, a maximum powder particle size of 12 to 13 microns isdesirable. Some moving bed operations use granular materials of -60 meshsize (60 mesh is about .246 mm.), and here particle sizes of about 1012microns will be found useful. In fluidized bed operations, the carrierparticles are much smaller, of the order of 150200 mesh (104 microns to74 microns, approximately), and frequently of sizes down to 20 microns.Since the usual desire is to modify or assist the operation of thecarrier particle which normally is the principal catalyst for thedesired reaction, and to avoid the possibility of mechanical segregationof mixed catalyst of similar sized particles, the adherence. principleshould be observed. To do so in the case of the finest carrierparticles, around 20 micron size, requires finely powdered crystallinealumino-silicate, with sizes of the order of 5 microns. In fixed bedoperations, the carrier particle sizes are of the order of 0.1 inch(2.54 mm.) and above, and powder sizes will be about the same as formoving bed operations.

The amount of crystalline alumino-silicate catalytic material to beadded depends upon the effect desired, the size of the pulverulentmaterial, and the nature of the material to which it is added. Withbeads, as described, of the conventional catalyst, an upper limit ofabout 5% or so by weight can be reached without serious change in theflow characteristics in the moving bed operation through which thecomposite passes. With fluidized bed operation, it will be possible touse higher concentrations, of the order of 10% by weight. With pelletand granular carriers so much depends upon the sizes, shapes, andsurfaces of the carrier material that determination of what amountcan'be used must be by experimentation, and the same is true for anytype of carrier in a static bed operation, where plugging of intersticesbetween particles becomes of major importance. In general, an upperlimit of about 10% by weight of the total mass is indicated.

it is also noted that the amount to be added Will vary with the purposedesired, since smaller amounts may be used to merely influence orslightly change the nature and course of a reaction being accomplishedby the major catalytic portion of the composite catalyst.

The conditions of operation, i.e., catalyst/oil ratio, liquid hourlyspace velocity, temperature, pressure, and the like will not vary to anygreat degree from those utilized for conventional catalytic materialsfor the same desired conversions, although due to the increased activityof the crystalline alumino-silicate catalysts, it will frequently bepossible to operate at somewhat lowertemperatures. The amount of thismodification will depend upon the proportionate amount of thecrystalline catalytic material present, being greatest, of course, inthose circumstances where the major catalysis emphasis is upon thecrystalline material itself and that material is present incomparatively large amount.

1 claim: a

l. in a method for the catalytic. conversion of hydrocarbons theimprovement which comprises contacting the hydrocarbons at conversionconditions with a contact mass comprising two components, one of whichis a particle form solid materialselected from the group consisting ofinert material and catalytic material ranging generally from 20 micronsupwardly to 0.1 inch and above, the average size of particles beingdependent upon the type of process, the second component comprising acrystalline aluminosilicate conversion catalyst said second componentbeing in the form of particles ranging downward in size from 15 microns,said second component having at least some material of not more than 5microns in size and snfiicient of said second component to substantiallycoat the particles of the first named component and to adhere to thesurfaces of the particles of the first named component.

2. The method of claim 1 in which the second component comprises asuperactive crystalline alurninosilicate.

3. The method of claim l in which the particle-form solid contact massmaterial moves as a descending bed through the area ofhydrocarboncontact, said bed being replenished at the top and havingportions thereof withdrawn at the bottom, with said powdered crystallinealuminosilicate conversion catalyst being added to the incomingparticle-form solid contact mass material in quantity sufficient tomaintain at least a partial coating thereof upon the particles in saidbed.

4. The method of claim 1 in which th solid contact material particlesare kept ina fiuidized bed condition by the passage of hydrocarbonreactant therethrough and in which powdered aluminosilicateconversion'catalyst is fed to said bed in quantity sufficient tomaintain at least a partial coating thereof upon the particles in saidbed.

5. The method of claim 1' in which the solid contact material particlesform a fixed bed through which hydrocarbon reactant is passed, the solidcontact material parti- 5 6 cles having been pre-coated at least in partwith the powpresent to the extent of up to about 5 percent by Weight ofdered crystalline aluminosilicate conversion catalyst. the total contactmaterial.

6. The method of claim 1 in which the powdered crystallinealuminosilicate conversion catalyst is present to References Cited y theExamine! the extent of up to about 10 percent by weight of the to- 5Cracking Catalyst, Ryland et al., Chapter I, page 76, tal Contactmatenah second paragraph in volume VII of Catalysis, Reinhold 7. Themethod of claim 1 in which the contact mass Publishing Co 19 0 New k ismaintained in the form of a moving bed and the powdered crystallinealuminosilicate conversion catalyst is ALPHONSO D. SULLIVAN, PrimaryExaminer.

1. IN A METHOD FOR THE CATALYTIC CONVERSION OF HYDROCARBONS THEIMPROVEMENT WHICH COMPRISES CONTACTING THE HYDROCARBONS AT CONVERSIONCONDITIONS WITH A CONTACT MASS COMPRISING TWO COMPONENTS ONE OF WHICH ISPARTICLE FORM SOLID MATERIAL SELECTED FROM THE GROUP CONSISTING OF INERTMATERIAL AND CATALYTIC MATERIAL RANGING GENERALLY FROM 20 MICRONSUPWARDLY TO 0.1 INCH AND ABOVE, THE AVERAGE SIZE OF PARTICLES BEINGDEPENDENT UPON THE TYPE OF PROCESS, THE SECOND COMPONENT COMPRISING ACRYSTALLINE ALUMINOSILICATE CONVERSION CATALYST SAID SECOND COMPONENTBEING IN THE FORM OF PARTICLES RANGING DOWNWARD IN SIZE FROM 15 MICRONS,SAID SECOND COMPONENT HAVING AT LEAST SOME MATERIAL OF NOT MORE THAN 5MICRONS IN SIZE AND SUFFICIENT OF SAID SECOND COMPONENT TO SUBSTANITALLYCOAT THE PARTICLES OF THE FIRST NAMED COMPONENT AND TO ADHERE TO THESURFACES OF THE PARTICLES OF THE FIRST NAMED COMPONENT.